Heating device for sheet-like object

ABSTRACT

A heating device is provided comprising a rotary transportation roller and pre-heated powder or granular bodies arranged and disposed around the periphery of said roller so that when a sheet-like, object to be processed is transported by said roller, said powder or granular bodies make direct contact with said object so as to heat the same.

United States Patent Umahashi et al.

[ Sept. 12, 1972 HEATING DEVICE FOR SHEET-LIKE OBJECT Inventors: Minoru Umahashi, Higashimatsuyama-shi; Hitoshi Yamakawa, Yokohama-shi; Motoyuki Suzuki, Tokyo, all of Japan Kabushiki Kaisha Ricoh, Tokyo, Japan Filed: Aug. 19, 1968 Appl. No.: 753,440

Assignee:

Foreign Application Priority Data Aug. 23, 1967 Japan ..43/53759 US. Cl. ..34/95 Int. Cl ..F26b 13/26 Field of Search.....34/9, 71, 95; 263/3; 101/416, 101/416.1, 416.2, 417, 418

References Cited UNITED STATES PATENTS 7/ 1962 Chipalkatti et al. ..34/9 X 3,248,798 5/1966 Burgess ..34/9

FOREIGN PATENTS OR APPLICATIONS 1,129,642 9/ l 956 France ..34/95 817,992 8/ 1959 Great Britain ..34/9

Primary Examiner-Frederick L. Matteson Assistant Examinerl-larry B. Ramey Attorney-Burgess, Ryan and Hicks [57] ABSTRACT 11 Claims, 1 Drawing Figure PATENTED SEP 12 I972 n u I n 1 INVENTORS Mmozu UMAHA sHi HiToSHi YAHAl-(AWA QT Y UKi SuzuKi BY MW M f ATTORNEY I HEATING DEVICE FOR SHEET-LIKE OBJECT BACKGROUND OF THE INVENTION The present invention relates to a device for drying or adjusting the water content of a moisture-containing order to adjust the water content within a predeterlo mined range of a sheet-like object such as paper or in order to thermally develop" a heat-sensitive paper, the heat of infrared rays is utilized, or a sheet-like object to be processed is interposed between a heating drum and a heat resisting sheet arranged and disposed around the heating drum so as to heat the sheet-like object through the heat resisting sheet. However, when the heat of the infrared rays is utilized, the thermal efficiency is reduced while when a heating drum is used, the sheet-like object cannot be dried uniformly or developing marks or blurs are produced because of the presence of water drops, the wrinkles etc.

Also known is a heating device of the type in which a sheet-like object to be processed is made to pass through a heated liquid. In this device it has been proposed to use as heating liquid mercury, a low-melting-point solder, etc., but mercury is too poisonous to be used in practice while the solder is also unpractical because the surface of the molten solder is oxidized by heat.

SUMMARY OF INVENTION In view of the above, the present invention provides a novel heating device comprising a rotary transportation roller and pre-heated powder or granular bodies arranged and disposed around the periphery of said roller so that when a web to be processed is transported by said roller, said powder or granular substances make direct contact with said web so as to heat the same.

The heating device can easily be adjusted so as to satisfy the particular heating conditions of sheet-like object to be processed. For example, the heating temperature of the powder or granular substances can be varied; the speed of a sheet-like object to be processed in contact with the powder or granular substances can be suitably adjusted; the quantity of the powder or granular substances to be charged can be varied so as to make adjustable the length of the processing operation of the sheet-like object; and the powder or granular substances can be replaced with difierent kinds or types of powder or granular substances so that the material and the particle size of the powder or granular substances can be changed.

One of the objects of the present invention is to eliminate the defects and disadvantages encountered when a conventional device of the type described is used and also to eliminate any developing mark or blur upon a sensitive paper to be thermally processed.

Another object of the present invention is to provide a heating device for sheet-like objects whose heating temperature can be easily adjusted.

Still another object of the present invention is to provide a heating device for sheet-like objects in which the transportation speed of a transportation roller can be varied and the matter shape, size, etc. of a heat-transferring material to be charged into the heating device can be easily replaced.

These and other objects and advantages of the present invention will be apparent from the following description of a preferred embodiment thereof taken in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF DRAWING v A single FIGURE, comprising a longitudinal sectional view of a heating device, illustrates the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT A feed or transporting roller designated by the reference numeral 1 is journaled in opposed side plates, one of which is shown at 2, of a machine frame and is I rotated in the direction indicated by the arrow by 1 For example, when the device of the present invention is employed in therrnography of a heat-sensitive paper, the roller 1 is made from a metal having good anticorrosiveness such as stainless steel, aluminum, copper, or the like and preferably is knurled so as to increase the coefficient of friction of the peripheral surface of the roller. The rotary speed or r.p.m. of the transporting roller 1 may be varied and adjusted suitably so as to satisfy the demand due to the peculiar heating characteristic of a heat-sensitive paper.

A plurality of slip wires 3 each having a suitable flexibility are disposed substantially along the outer peripheral surface of the transporting roller 1. These wires or guides extend circumferentially around the lower portion of roller 1 and are spaced longitudinally of each other. One end of the slip wires 3 is engaged with a shaft 4 fixedly secured to the opposed side plates 2 and 20 at the inlet of the heating device while the other end is bent around a fixed shaft 6 at the outlet of the heating device and is further engaged with a shaft 8 secured to said opposed side plates 2 and 2a through a spring 7. Therefore, the slip wires 3 are always under the tension of the springs 7. Advantageously, the slip wires 3 are made from a material having a high resistance to abrasive wear and a low coefficient of friction, such as a copper wire coated with fluorine-containing resin.

A U-shaped or open top container 5 is disposed between the opposed side plates 2 and 20 by means of the shaft 6 and another shaft 9 both of which are fixedly secured to the opposed side plates. In the annular space or gap 10 defined by the transportation roller 1 and the U-shaped container 5 there is a bed of subdivided solids in the form of powder or granules 11 having good thermal conductivity and the transporting roller 1 is adapted to rotate in such powder 11. As may be seen, the annular space 10 does not extend completely around the roller 1 but extends annularly along and beneath the lower periphery of the roller, and the powder fills this space. At suitable positions within the above described space or gap 10 are disposed a suitable number of heating elements, such as sheathed heaters 12, 12a, and 12b, thereby heating the powder or granule 11. In order to maintain at a predetermined temperature the powder or granule 11 disposed in the proximity of the peripheral surface of the transporting roller 1, there are provided thermostat 13, 13a, and 13b to thereby energize or deenergize the heating elements 12, 12a, and 12b so as to control the temperature.

Between the space defined by the U-shaped container and the outer chamber 14 a heat-insulating material 15 is present in order to prevent the dissipation of heat. Also in the space are arranged and disposed a supply pipe or conduit 16 and a discharge pipe or conduit 17 extending through the insulating material and the outer chamber 14 in order to supply and discharge the powder respectively. The

discharge pipe or conduit 17 is provided with a cock 18 in order to control the quantity discharged of the powder 11. The supply pipe or conduit 16 is connected to a supply tank (not shown) while the discharge pipe or conduit 17, to an accummulating tank (also not shown). The supply and accumulating tanks are interconnected with each other by means of a conduit provided with a pump so that the powder or granule accumulated in the accumulating tank arranged and disposed downwardly of the supply tank may be freely returned to the supply tank as need demands. At the inlet 30 of the heating device is arranged and disposed a feed roller 19 which is adapted to rotate by the rotation of the transporting roller 1. A follower roller 20 is arranged and disposed in contact with the feed roller 19 a0 as to be rotated thereby. Reference numeral 21 designates a feed guide plate. At the outlet of the heating device are arranged and disposed a transfer or pull roller 22 adapted to be rotated by the transportation roller 1 and a follower roller 23 adapted to be driven by the transfer roller 22. Reference numeral 24 designated a transfer or discharge guide plate which is provided with a pawl 25 at the end of the guide plate in contact with the transportation roller 1, whereby the leading end of the heat-processed sensitive paper is separated from the transportation roller 1 and dischargedout of the heating device. As may be appreciated, the structures 19, 20, and 21 comprise means for introducing the web between the roller 1 and the guides 3, while the structures 22, 23, 24, and 25 comprise means for removing the web from roller 1.

The pair of feed rolls 19 and 20 and the pair of transfer or discharge rollers 22 and 23 are coveredwith an upper cover 27 having therein heat-insulating material 26. Reference numeral 28 designates a heatsensitive paper to be charged into the heating device while 29, a thermally processed sensitive paper to be discharged from the heating device. Reference numeral 31 designates an outlet for discharging the processed paper 29.

Next the mode of operation of the heating device according to the present invention will be described. First a sensitive paper to be thermally processed by the device is charged or fed into the device through the inlet so as to be held between the pair of feed rollers 19 and 20. Then the sensitive paper is interposed by means of the guide plate 21 between the feed roller 19 and the transportation roller 1 and then transported or advanced by the transportation roller 1 through the guides or slip wires 3. In this case, the sensitive layer of the paper is directly contacted with and heated by the powder which is heated at a predetermined temperature so that the sensitive paper is suitably thermally processed or developed. Thus thermally processed or developed sensitive paper is further transported forwardly by the transportation roller 1 and is finally guided to be interposed between the transportation roller 1 and the transfer or discharge roller 22. Thereafter the sensitive paper is separated from the transporting roller 1 by means of the pawl 25, interposed between the transfer or discharge rollers 22 and 23 by means of the guide plate 24 and finally discharged out of the heating device through the outlet 31.

As to the powder to be charged in the space 10, there may be mentioned finely divided aluminum, aluminum particles, glass beads, stainless steel beads or steel balls which have been finished by surface treatment. The powder actually comprises a stationary bed in the space 10. The particle size of the powder may be suitably selected depending upon the thermal processing condition required at each time. As described in detail hereinbefore, the present invention permits the direct conduction of heat in heattransfer from the heating elements to the sensitive layer of the sensitive paper; and

furthermore heat loss is minimized and the uniform temperature distribution in the proximity of the sensitive layer of the sensitive paper can be maintained by enclosing the thermal conduction or heat-transfer region with the heat-insulating material.

As is well known among those skilled in this art, in case of the heating system employing a heating drum, the water contained in a sensitive paper to be processed is caused to be evaporated so that the uniform contact between the sensitive paper and the drum cannot be ensured due to the vapor produced as described above, whereby the developing marks or blurs are observed on the processed paper. On the other hand, according to the present invention, the vapor or steam produced during the processing operation can leak out through the gaps between the powder so that there is no fear at all of causing developing marks or blurs upon the paper. Furthermore, the close contact between the powder and the sensitive layer of the sensitive paper can be maintained so that the heat can be transferred effectively with high efficiency from the powder to the sensitive layer of the sensitive paper.

Moreover, according to the present invention the temperature for thermally processing the sensitive paper can be suitably adjusted by the disposition of the thermostats within the powder of in the proximity of the sensitive layer of the sensitive paper. Furthermore, since a plurality of heating elements are arranged and disposed, a suitable temperature gradient may be produced in the direction from the inlet toward the outlet.

In the heating device according to the present invention, a suitable heating condition can be obtained by varying the peripheral speed of the transportation roller, adjusting the quantity or powder to be charged, varying the powder or granule material and its size and or by combinations of the above described steps or means.

So far the invention has been described as a thermographic device, but it is not limited thereto. It is obvious to those skilled in the art that the invention can be applied to a drying device or moisture adjusting device for a sheet-like object. Therefore, it should be noted that the foregoing description is merely an illustration of one preferred embodiment of the invention and is not intended to limit the invention to this illustrative embodiment.

What is claimed is:

1. A heating device for heating a moisture-containing web or other sheet-like object comprising a chamber having a container supported therein, a rotatable roller disposed in the container in spaced relation thereto so as to form a space therebetween, a stationary bed of subdivided solids in said space, means in the bed for heating the same, a plurality of longitudinally spaced guides extending circumferentially around at least the lower portion of said roller and being in contact with the surface of said bed, means for introducing a moisture-containing web between said roller and said guides for rotary movement with the roller, said web making contact with the roller and with the surface of the heated bed and moving into and out of contact with said bed during rotation of the roller, said web thereby becoming heated and reduced inmoisture content and the released moisture passing into said bed of solids, and means for removing the web from the roller after passage of the web over the surface of the bed.

2. Device of claim 1 wherein said container has an open upper portion and curved walls which substantially correspond to the curvature of the roller.

3. Device of claim 1 wherein said space is an annular space that extends along the lower periphery of said roller and wherein said solids fill said space beneath said roller.

4. Device of claim 1 wherein said guides comprise tensioned wires.

5. Device of claim 1 wherein said moisture-containing web is a heat-sensitive paper, and the heated moisture-reduced web comprises a thermallyprocessed sensitive paper that is free of developing marks and blurs.

6. Device of claim 1 wherein said heating means comprise thermostatically-controlled electric heaters disposed one behind the other within said bed.

7. Device of claim 1 wherein said container has means for removing solids from a lower pom'on thereof and for introducing solids to an upper portion thereof.

8. Device of claim 1 wherein said web-removing means comprises a pawl.

9. A heating device for heating a moisture-containing web or other sheet-like object comprising a chamber having supported therein a U-shaped container with curved side walls, a rotatable roller disposed in the container in spaced relation thereto so as to form an annular space therebetween, a stationary bed of subdivided solids in said space, said bed filling the space beneath the roller, means spaced along and'disposed in the bed for heating the same, a plurality of spaced tensioned guides extending circumferentially around at least the lower portion of the roller, means for introducing a moisture-containing web between said roller and guides for rotary movement with said roller, said web making contact with the roller and with the surface of the heated bed and moving into and out of contact with the bed during rotation of the roller, said web thereby becoming heated and reduced in moisture content and the released moisture assingbinto said bed of solids, means for removing e we from the roller after passage of the web over the surface of the bed, andmeans on the container for removsolids from a lower portion thereof and for introducing solids to an upper portion thereof.

10. A device for heating a strip of heat sensitive photocopying paper or the like comprising a non-v fluidized bed of granular solid particles having an upper surface, heating means for heating said bed to a desired temperature, a transportation roller rotatable about a substantially horizontal axis and partially submerged in the bed, meansfor feeding the strip along an entrance path into contact with the roller at a position on the roller surface above the upper surface of the bed,

means for leading the strip from the roller-at a position on the roller surface above the upper surface of the bed after said strip has passed around the roller beneath the surface of the bed, and pressure means for pressing the strip into close frictional engagement with the surface of the roller at locations below the surface of the bed, said pressure means comprising wire-like elements extending around the periphery of the roller beneath the surface of the bed, each said element lying in a plane perpendicular to the axis of the roller and each said element having means for tensioning it in a longitudinal direction and wherein the device further comprises input feed means for guiding the strip along a curved path into a path tangent to the surface of the transportation roller at a position on the roller at which the roller surface is about to enter the bed, said input feed means comprising a curved guide plate, and output feed means comprising a curved doctor blade for guiding the strip away from the roller at a position on the roller which has just emerged from the bed.

11. A device for heating a strip of heat sensitive photocopying paper or the like comprising a nonfluidized bed of granular solid particles having an upper surface, heating means for heating said bed to a desired temperature, a transportation roller rotatable about a substantially horizontal axis and partially submerged in the bed, means for feeding the strip along an entrance path into contact with the roller at a position on the roller surface above the upper surface of the bed, means for leading the strip from the roller at a position on the roller surface above the upper surface of the bed after said strip has passed around the roller beneath the surface of the bed, and pressure means for pressing the strip into close frictional engagement with the surface of the roller at locations below the surface of the bed, said pressure means comprising wire-like elements extending around the periphery of the roller beneath the surface of the bed and means for tensioning said elements and thereby creating a radially inward pressure of said elements against the strip, said elements having a coefficient of friction against the strip less than that of the surface of the roller against the strip. 

1. A heating device for heating a moisture-containing web or other sheet-like object comprising a chamber having a container supported therein, a rotatable roller disposed in the container in spaced relation thereto so as to form a space therebetween, a stationary bed of subdivided solids in said space, means in the bed for heating the same, a plurality of longitudinally spaced guides extending circumferentially around at least the lower portion of said roller and being in contact with the surface of said bed, means for introducing a moisture-containing web between said roller and said guides for rotary movement with the roller, said web making contact with the roller and with the surface of the heated bed and moving into and out of contact with said bed during rotation of the roller, said web thereby becoming heated and reduced in moisture content and the released moisture passing into said bed of solids, and means for removing the web from the roller after passage of the web over the surface of the bed.
 2. Device of claim 1 wherein said container has an open upper portion and curved walls which substantially correspond to the curvature of the roller.
 3. Device of claim 1 wherein said space is an annular space that extends along the lower periphery of said roller and wherein said solids fill said space beneath said roller.
 4. Device of claim 1 wherein said guides comprise tensioned wires.
 5. Device of claim 1 wherein said moisture-containing web is a Heat-sensitive paper, and the heated moisture-reduced web comprises a thermally-processed sensitive paper that is free of developing marks and blurs.
 6. Device of claim 1 wherein said heating means comprise thermostatically-controlled electric heaters disposed one behind the other within said bed.
 7. Device of claim 1 wherein said container has means for removing solids from a lower portion thereof and for introducing solids to an upper portion thereof.
 8. Device of claim 1 wherein said web-removing means comprises a pawl.
 9. A heating device for heating a moisture-containing web or other sheet-like object comprising a chamber having supported therein a U-shaped container with curved side walls, a rotatable roller disposed in the container in spaced relation thereto so as to form an annular space therebetween, a stationary bed of subdivided solids in said space, said bed filling the space beneath the roller, means spaced along and disposed in the bed for heating the same, a plurality of spaced tensioned guides extending circumferentially around at least the lower portion of the roller, means for introducing a moisture-containing web between said roller and guides for rotary movement with said roller, said web making contact with the roller and with the surface of the heated bed and moving into and out of contact with the bed during rotation of the roller, said web thereby becoming heated and reduced in moisture content and the released moisture passing into said bed of solids, means for removing the web from the roller after passage of the web over the surface of the bed, and means on the container for removsolids from a lower portion thereof and for introducing solids to an upper portion thereof.
 10. A device for heating a strip of heat sensitive photocopying paper or the like comprising a non-fluidized bed of granular solid particles having an upper surface, heating means for heating said bed to a desired temperature, a transportation roller rotatable about a substantially horizontal axis and partially submerged in the bed, means for feeding the strip along an entrance path into contact with the roller at a position on the roller surface above the upper surface of the bed, means for leading the strip from the roller at a position on the roller surface above the upper surface of the bed after said strip has passed around the roller beneath the surface of the bed, and pressure means for pressing the strip into close frictional engagement with the surface of the roller at locations below the surface of the bed, said pressure means comprising wire-like elements extending around the periphery of the roller beneath the surface of the bed, each said element lying in a plane perpendicular to the axis of the roller and each said element having means for tensioning it in a longitudinal direction and wherein the device further comprises input feed means for guiding the strip along a curved path into a path tangent to the surface of the transportation roller at a position on the roller at which the roller surface is about to enter the bed, said input feed means comprising a curved guide plate, and output feed means comprising a curved doctor blade for guiding the strip away from the roller at a position on the roller which has just emerged from the bed.
 11. A device for heating a strip of heat sensitive photocopying paper or the like comprising a non-fluidized bed of granular solid particles having an upper surface, heating means for heating said bed to a desired temperature, a transportation roller rotatable about a substantially horizontal axis and partially submerged in the bed, means for feeding the strip along an entrance path into contact with the roller at a position on the roller surface above the upper surface of the bed, means for leading the strip from the roller at a position on the roller surface above the upper surface of the bed after said strip has passed around the roller beneath the surface of the bed, and pressure means for pressing the strip into close frictional engagement with the surface of the roller at locations below the surface of the bed, said pressure means comprising wire-like elements extending around the periphery of the roller beneath the surface of the bed and means for tensioning said elements and thereby creating a radially inward pressure of said elements against the strip, said elements having a coefficient of friction against the strip less than that of the surface of the roller against the strip. 